<p>What are the subject tests you have already taken? What are your regular SAT scores? What colleges are you looking at? What is your proposed major? All of those could make a difference in the answer to this question.</p>
<p>If the two you already took were both arts subjects, then you might want to take one in a math/science subject (or the other way around). It just makes you seem well rounded if you can do well on both kinds of tests. But it is not necessary by any means. By the way, those are great scores, congrats!</p>
<p>The exact subjects are more important than the number of subject tests. If you have a bunch of social science and languages SAT2, it won’t do any good for MIT for instance. Also, if any of the 2 subject tests you have taken is your native foreign language, it may not be qualified as part of the requirement. In general, for any science and engineering major, you need one math (preferably Math2) and one science. For some top schools like Harvard, they like to see more subject test scores although the impact would be small.</p>
<p>It’s not going to hurt if you prepare for chem and get at least 700. If anything, if you can focus on something more important, do. If you don’t have much to do… Study for chem and take it. Won’t hurt.</p>